the rest of it rubs on the plastic parts that stick out. that plastic will scratch the black area cuz that area is plastic
https://youtu.be/XJP6gERPmMk?t=307
not to make it sound like im trying to **** on the switch, this guy breaks down phones for a youtube living and he does say that overall the system is very durable (you can see him give it the bend test at the end)